Self adjusting tangency-clearance compressor with liquid purge capability

ABSTRACT

A vane-type compressor especially adapted for compressing refrigerant in air-conditioning systems has a vane carrying rotor mounted on fixed center bearings and surrounded by an eccentrically positioned cylinder guiding the vane motion and confining and controlling the compression process which is free to swing toward the rotor and maintain a line of tangency contact therewith providing a direct barrier between the discharge and suction sides of the compression chamber. A spring loaded end plate pressed against one end of the cylinder serves as a relief valve to purge liquid such as lubricant which might collect in the compression cavities during a shut-down period and which could otherwise create a lock-up condition. A fixed front bearing plate or end head has a cup-shaped housing piloted thereon surrounding the cylinder and providing a rear bearing mounting for the rotor. The front plate has an inlet port supplying the compression cavities between the rotor and cylinder. The cylinder has an outlet adjacent the tangency seal line of contact between the rotor and cylinder which discharges to a chamber between the housing and cylinder that is surrounded by porous fibrous strips effective to separate lubricant entrained in the compressed refrigerant. The refrigerant is discharged to an outlet port in the front bearing plate and the separated lubricant collects in the bottom of the housing and is circulated back to the bearings and vane slots of the rotor.

United States Patent [1 1 Allen 1 SELF ADJUSTING TANGENCY-CLEARANCECOMPRESSOR WITH LIQUID PURGE CAPABILITY [75] Inventor: Clifford H.Allen, Chesterland, Ohio [73] Assignee: TRW Inc., Cleveland, Ohio [22]Filed: Dec. 5, 1973 [21] Appl. No.: 421,988

[52] U.S. Cl 417/283, 417/310, 418/97,

[51] Int. CL... F0lc 19/00, FOlc 21/04, F04b 49/00 [58] Field of Search418/107, 30, 97, 98, 99;

[56] References Cited UNITED STATES PATENTS 2,447,744 8/1948 Duemler417/310 X 2,700,341 1/1955 Smirl 3,652,191 3/1972 King et a1. 418/1253,743,445 7/1973 Dworak 417/220 Primary ExaminerCarlton R. CroyleAssistant ExaminerRichard E. Gluck Attorney, Agent, or Firml-lill,Gross, Simpson, Van Santen, Steadman, Chiara & Simpson [57] ABSTRACT Avane-type compressor especially adapted for com- 1 Feb. 11, 1975pressing refrigerant in air-conditioning systems has a vane carryingrotor mounted on fixed center bearings and surrounded by aneccentrically positioned cylinder guiding the vane motion and confiningand controlling the compression process which is free to swing towardthe rotor and maintain a line of tangency Contact therewith providing adirect barrier between the discharge and suction sides of thecompression chamber. A spring loaded end plate pressed against one endof the cylinder serves as a relief valve to purge liquid such aslubricant which might collect in the compression cavities during ashut-down period and which could otherwise create a lock-up condition. Afixed front bearing plate or end head has a cupshaped housing pilotedthereon surrounding the cylinder and providing a rear bearing mountingfor the rotor. The front plate has an inlet port supplying thecompression cavities between the rotor and cylinder. The cylinder has anoutlet adjacent the tangency seal line of contact between the rotor andcylinder which discharges to a chamber between the housing and cylinderthat is surrounded by porous fibrous strips effective to separatelubricant entrained in the compressed refrigerant. The refrigerant isdischarged to an outlet port in the front bearing plate and theseparated lubricant collects in the bottom of the housing and iscirculated back to the bearings and vane slots of the rotor.

26 Claims, 10 Drawing Figures SELF ADJUSTING TANGENCY-CLEARANCECOMPRESSOR WITH LIQUID PURGE CAPABILITY BACKGROUND OF THE INVENTION 1.Field of the Invention This invention relates to the art of tangencysealed vane-type compressors and particularly deals with a compressorhaving a free swinging cylinder contacting the rotor along a line oftangency between the high pressure and low pressure compressor cavitieswith a sealing force established by the pressures in the cavities andhaving wick means separating liquid from compressed gases together withrelief means preventing liquid lock-up of the rotor.

2. Prior Art The volumetric efficiency of vane-type compressors isdependent upon close clearances between the internal components tominimize leakage between high pressure and low pressure cavities and aparticular critical leakage path is across the line of contact betweenthe rotor and cylinder commonly referred to as the line of tangency.Since this line is a direct barrier between the discharge and suctionpressures of the compressor, any leakage across the line involves a lossof compression work done on the leakage volume. In spite of the bestefforts in assembling prior art compressors to set the tangency lineclearance as close to zero as possible, these clearances tend to getlarger in actual service due to operating factors such as differentialthermal expansion, pressure loading on the rotor and cylinder tending todrive them apart, hydrodynamic lubricating oil forces and wear andbearing clearances.

One of the disadvantages of the use of tangency seals to controltangency line leakage is inherent in the ne' cessity for said seals tomaintain sealing contact with the surface of the rotor whilesimultaneously permitting the uninhibited movements of the vanes pastthe tangency line. Such a seal is difficult to design and construct, issubject to fatigue and to the likelihood of mechanical interference withthe vane movement.

In my prior U. S. Pat. No. 3,729,277 issued Apr. 24, [973, there isdisclosed and claimed a tangency sealed vane compressor which avoidedmany of the deficien cies of the earlier prior art. In this patentedcompressor, the cylindrical compression chamber defining member waspivoted so that upon assembly it could be swung into a tangency sealline of contact with the rotor and then be locked in this sealingposition. In this construction the rotor and cylinder componentstogether with a rear bearing plate were stacked on the front bearingplate or main end head of the compressor and the stacked assembly wasmounted to this end head by draw bolts which did not provide a positivealignment of the rotor shaft bearings nor could it accommodate relief ofliquid which might collect in the compression cavities during periods ofnon-use and might tend to lock up the rotor especially on rapid starts.Further, any wear at the initially created tangency line of contactbetween the rotor was not automatically taken up nor was the sealingload dependent upon the pressures in the pressure cavities. In addition,pivoting of the cylinder on the pins extended into the end faces of thecylinder required accurate centering of holes for the pins.

SUMMARY OF THIS INVENTION According to this invention theabove-mentioned deficiencies of the prior art are eliminated by pilotingthe rear bearing support for the rotor shaft on the front main bearingplate or end head to insure accurate alignment ofthe front and rearshaft bearings, by pivoting the cylinder on its outer periphery midwaybetween its end faces, by allowing the cylinder to swing on its pivotduring operation of the compressor so that the tangency seal load willbe controlled by the pressures in the high-pressure cavities of thecompressor and by providing a retractable end plate for the rotor andcylinder which will release liquid from the compressor cavities toprevent lock-up upon starting. In addition, the invention provides wickmeans for separating lubricant which might be entrained with compressedrefrigerant enroute to the outlet port. The separated lubricant iscollected in a sump provided in the bottom of the compressor housing andis recirculated back to the bearings and vane slots to lubricate thebearings and vanes.

The pivot for the cylinder is a shoe carried by the housing. A springalso carried by the housing urges the cylinder to rotate about its pivotinto contact with the rotor to maintain a minimum load tangency sealwhich, of course, is additionally loaded by the pressures in thecompression cavities. This arrangement eliminates the heretoforerequired accurate positioning of pivot pins and prevents binding of theswinging of the cylinder.

The cylinder is surrounded in spaced relation by a cup-shaped housingpiloted on the end head or front bearing plate of the compressor and hasoutlet holes in the top thereof immediately ahead of the tangency lineof contact with the rotor which discharge the compressed refrigerantinto a localized compartment between the cylinder and housing bounded byfibrous strips. The refrigerant passes through these strips to an outletport in the front hearing plate or main end head of the compressor. Anylubricant entrapped with the compressed refrigerant is wicked from therefrigerant by the fibrous strip material and accumulates to drip downto a collection sump in the bottom of the housing. A passageway in theend head conveys the collected lubricant from the sump through the shaftbearings and center of the rotor for lubricating the bearings and thevanes.

While this invention is specifically described as embodied in avane-type refrigerant compressor especially adapted for air-conditioningsystems, it should be understood that the principles of this inventionare applicable to any tangency seal-type of pump or compressor and thatthe rotor instead of carrying vanes could carry slippers, rollers or thelike finger members riding on the cylinder to create the isolatedcavities between the eccentrically related outer periphery of the rotorand inner periphery of the cylinder. Therefore, the term, vane-typecompressors, as used herein will serve to encompass pumps, motors, andcompressors having eccentrically related rotors and encompassing chamberdefining members on which fingers projecting from the rotor will rideand wherein the rotor has a tangency seal relationship with theencompassing member between the high pressure and low pressure sides ofthe device.

It is then an object of this invention to enhance the volumetricefficiency of tangency seal-type rotary pumps, motors and compressors byproviding a free swinging rotor housing maintaining the tangency seal.

Another object of the invention is to provide a selfliquid purging gasor vapor compressor.

Another object of the invention is to provide a vapor or gas compressorseparating liquid from the compressed gas or vapor and utilizing theliquid to lubricate the compressor parts.

Another object of this invention is to provide a rotary vane compressorwith a free swinging rotor encompassing cylinder which guides the vanesand establishes a tangency seal between the high and low pressure sidesof the compressor at a sealing load created by the pressures in thecompressor cavities.

Another object of the invention is to provide a rotary vane compressorwith a swinging rotor encompassing cylinder on which the vanes ridewhich is spring-loaded into sealed contact with the rotor along a lineof tangency between the high pressure and low pressure compressorcavities.

A further object of the invention is to provide a rotary vane compressorwith a housing cylinder pivoted on an external shoe and swung into atangency sealing line of contact with the rotor under the influence ofpressures in the compressor cavities between the rotor and cylinder.

A further object 'of the invention is to provide a rotary vanecompressor with a rotor mounted on fixed center bearings, a cylindersurrounding the rotor in eccentric relation, a housing surrounding thecylinder in spaced relation and a pivot shoe carried by the housingallowing the cylinder to swing for establishing and maintaining atangency seal line of contact with the rotor between the high pressureand low pressure sides of the compressor.

A still further object of the invention is to provide a refrigerantcompressor especially suited for airconditioning systems having a frontbearing carrying end head, a bearing carrying cup housing piloted on theend head, a vane carrying rotor mounted on a shaft supported in bearingscarried by the end head and cup housing, a cylinder in the housingsurrounding the rotor and guiding the rotor vanes, a pivot shoe carriedby the housing cooperating with the periphery of the cylinder, a springswinging the cylinder about the pivot shoe into sealed contact with therotor, a spring loaded end plate in the housing pressed against an endface of the cylinder and adapted to be deflected therefrom and meansbetween the housing and cylinder for separating lubricant fromrefrigerant compressed by the rotor and vane.

Other and further objects of this invention will become apparent tothose skilled in this art from the following detailed description of theannexed sheets of drawings which by way of a preferred exampleillustrate one embodiment of the invention.

IN THE DRAWINGS FIG. 1 is a front end elevational view of a rotary vanecompressor of this invention;

FIG. 2 is a longitudinal, cross sectional view taken along the lineII--II of FIG. 1;

FIG. 3 is a transverse cross sectional view taken along the line III-IIIof FIG. 2;

FIG. 4 is a transverse, cross sectional view taken along the line IV-IVof FIG. 4;

FIG. 5 is a fragmentary plan view along the line V-V of FIG. 6;

FIG. 6 is a cross sectional view along the line VI.-Vl of FIG. 5;

FIG. 7 is a transverse, cross sectional viewalong the line VII--Vll ofFIG. 3; v

FIG. 8 is a somewhat diagrammatic view similar to FIG. 3 showing theforces for swinging the cylinder into tangency sealed relation with therotor;

FIG. 9 is a view similar to FIG. 3 but with the internal parts omittedto show the back wall of the cup-shaped housing; and

FIG. 10 is a cross sectional view along the line X-X of FIG. 1.

As shown in FIGS. 1 and 2, the compressor 10 has a front bearing plateor main end head 11, a cup-shaped housing 12 with a cylindrical month 13seated on a cylindrical pilot portion 14 of the end head 11 and hottomedagainst an end shoulder 15 of the end head. An O-ring seal 16 isconfined between the mouth 13, the pilot l4 and the end face 15. The cuphousing 12 has internally threaded boss portions 17 spaced around itsperiphery as shown in FIGS. 2 and 3 opening to the shoulder 15 of theend head 11 and bolts 18 having heads bottomed on the outer face of theend head 11 are threaded into these bosses to unite the end head 11 andcup 12 in integral, fixed, sealed relationship.

The end head 11 as shown in FIGS. 1, 2, and 4 has an inlet port 19 andan outlet port 20. A relief valve 21 communicates with the portpassageway 20 to relieve excess pressures which might damage the systemsupplied by the compressor. The end head also has legs 22 and bosses 22ato mount the compressor in a refrigerant system such as an automobileair-conditioning system assembly.

A hub 23 at the center of the end head 11, as shown in FIG. 2, has acylindrical bore 24 therethrough with an enlarged counterbore 25 at theinner end thereof. This counterbore mounts a ball bearing assembly 26which is held against the shoulder 27 between the counterbore 25 andbore 24 by a snap ring 28.

A shaft seal assembly 29 is mounted in the bore 24 including a shaftmounted spring loaded face ring part 29a and a hub mounted fixed matingring part 29b held in the bore 24 by a snap retaining ring 30.

A rotor shaft 31 projects through the hub 23 of the end head 11 into acylindrical hub 32 projecting from the rear end 33 of the cup-shapedhousing 12 toward the end head 11. Roller or needle bearings 34 supportthis end of the shaft 31 in the hub 32 of the housing 12.

The shaft 31 has retainer rings 35 projecting from grooves therein intoabutting relation with both end faces of the inner race ring of the ballbearing assembly 26, thereby holding the shaft against axial shiftingrelative to the hubs 23 and 32.

It will therefore be understood that the shaft 31' is rotatably mountedon bearing supports provided by the end head 11 and the housing 12 whichis accurately piloted on this end head so that true alignment of thebearing supports is established and maintained.

The rotor 36 for the compressor 10 is mounted on the rotor shaft 3' 1for corotation therewith The rotor 36 has four radial slots 37 inequally spaced circumferential relation extending inwardly from pockets38 in the periphery of the rotor as shown in FIG. 3 for a depth toaccommodate the height of vanes 39 slidably mounted therein when shoes40 on the ends of the vanes are retracted into the pockets. Two pairs ofpins 41 and 42 extend through holes through the shaft and inner portionof the rotor into the slots 37 and receive coil springs 43 therearoundacting on the inner ends of the vanes 39 to urge them outwardly from thebottoms of the slots. Thus, one pair of pins 41 with the springs 43therearound act on one pair of diametrically opposite vanes 39 while theother pair of pins 42 and their springs 43, offset from the pins 41, acton the other pair of diametrically opposite vanes 39.

A cylinder 44 as shown in FIGS. 2 and 3 is mounted in the housing 12 andenvelops the rotor 36. This cylinder has an inner peripheral wall 45eccentrically related to the periphery 46 of the rotor 36 and spacedtherefrom except at a single line of contact 47 at the point of tangencybetween the cylinder and rotor to establish a tangency seal between thelow and high pressure sides of the compressor. The vanes 39 projectingfrom the rotor to have their slippers or pivot ends 40 riding on theinner wall 45 of the cylinder 44 divide the space between the wall 45 ofthe cylinder 44 and the periphery 46 of the rotor 36 into cavitiesreceiving refrigerant from the inlet port 19 and discharging compressedrefrigerant to the outlet port 20 as will be more fully hereinafterexplained.

The cylinder 44 is pivoted in the housing 12 on a shoe 48 carried by arib 49 of the housing 12 which projects inwardly from the periphery ofthe housing in circumferentially spaced relation upstream from thetangency seal line 47. The shoe 48 has a nose 48a seated in a groove orrecess 50 of a pivot plate 51 which is bolted to a flat peripheralportion 52 of the cylinder 44 by means of bolts 53. The rib 49 carryingthe shoe 48 and the recess 50 receiving the nose 48a of the shoe must belocated within relatively broad limits at a point on the circumferenceof the cylinder 44 where the resultant couple due to pressures in thecylinder tends to pivot the cylinder in a direction tending to eliminateclearance at the line of tangency between the cylinder and rotor 36.However, in manufacture, tolerances relative to locations of the pivotare not critical.

A reed valve 54 composed of a thin metal plate is clamped under theplate 51 by the bolts 53 and as shown in FIG. 3 the plate 51 is bowedoutwardly from the flat surface 52 of the cylinder 44 at its unbolted orfree end so that the reed valve 54 may be deflected outwardly from itsseat on this flat area 52.

The cylinder 44 has a row of outlet ports 55 therethrough underlying thefree end of the reed valve 54 and positioned just upstream or ahead ofthe tangency seal line 47 of the cylinder 44 with the rotor 36. Thecompressed refrigerant is discharged through these ports 55 and raisesthe reed valve 54 to flow into a localized chamber 560 separated fromthe main annular space 56 between the housing 12 and cylinder 44 byfibrous side strips 57 extending from the end head 11 to the back wall33 of the housing 12. The inner ends of these strips 57 are seated ingrooves 58 and the outer ends of these strips fit between ribs 59 on theinner periphery of the housing 12 as shown in FIG. 3. The rear end ofthis localized chamber 56a is bounded by a third fibrous strip 60 which,as shown in FIG. 2, spans the gap between the back wall 33 of thehousing 12 and an end plate 61 which is bottomed on the end face of thecylinder 44 to define with the cylinder and end head 11, the workingchamber of the compressor. The plate 61 is pivotally seated on the hub32 of the end wall 33 of the housing 12 and an o-ring seal 62 seals theinner periphery of the plate to the hub but accommodates tilting andsliding of the plate on the hub.

As shown in FIGS. 9 and 10, the plate 61 is spring pressed against theend of the cylinder 44 by a plurality of coil springs 63 seated inpockets defined by ribs 64 projecting from the end wall 33 of thehousing 12. The strip 60 is bent over one of these pocket-defining ribs64 as shown in FIG. 9 and has its end legs seated between opposed ribs65. The strip 60 is sufficiently resilient so that the plate 61 may tiltor slide away from the cylinder 44 to provide its relief function asmore fully hereinafter described.

To facilitate opening of the reed valve 54 by the compressed refrigerantfrom the ports 55, the valve plate 54, as shown in FIGS. 5 and 6, has aU-shaped slot 66 isolating a tongue 69 which underlies the embossmentforming the groove 50 in the pivot plate 51 that receives the nose 48aof the shoe 48. In this manner, the free end of the reed valve 54 canflex without interference from the embossed portion of the overlyingplate.

The compressed refrigerant in the localized chamber 56a flows throughthe strips 57 and 60 into the main space or chamber 56 where it iseffective to cooperate with the springs 63 in holding the plate 61against the cylinder 44. The strips are composed of a fibrous materialwhich will coalesce or wick out the lubricant entrained in thecompressed refrigerant. Such materials are optically opaque, syntheticfibers and are known in the trade as synthetic felt composed of nylon,Dacron (trademark) and the like. The felt is porous and is wet by theoil lubricant thereby acting as a demister. The material must be capableof withstanding high temperatures in the order of 400F.

To prevent liquid, such as oil, in the system from building up to form aliquid wedge tending to open up the tangency seal 47, the cylinder 44has a plurality of bleeder holes 550 therethrough downstream from theport holes and just ahead of the tangency seal line as shown in FIGS. 3,5, and 8. These bleeder holes vent to the chamber 56a any oil trapped atthe tangency line.

The compressed refrigerant free of lubricant in the chamber 56 flows tothe outlet port 20 in the end 11 from which it is discharged.

The wicked-out oil drips from the fibrous strips 57 and to the bottom ofthe housing 12 where, as shown in FIG. 2, it collects in a pond P whichis exposed to the pressure of the compressed refrigerant in the chamber56. The end head 11 is drilled to provide a passageway 68 joining thepond P with the hub 23 behind the seal ring 29b so that oil backed bypressure in the chamber 56 flows from the pond into the hub to lubricatethe shaft seal 29 and the bearing 26. From the bearing 26 the pressuredoil flows through the vane slots 37 of the rotor to lubricate the vanes39 and cylinder wall 45 and also flows into the hub 32 to lubricate therear bearing 34. Thus the oil is returned to the cavities between therotor and cylinder, and the moving parts of the compressor are amplylubricated from oil that is separated from the compressed refrigerantand returned to the refrigerant being compressed.

In the event the compression cavities between the rotor and cylinderbecome flooded with oil during periods of non-use of the compressor,lock-up of the rotor during rapid start-ups by this oil is preventedbecause liquid in the compressor cavities between the rotor and cylinderwall, when pumped by the vanes 39, will unseat the plate 61 from the endface of the cylinder allowing this liquid to escape to the pond P. Thespring load on the plate 60 is calibrated so that the plate will unseatat pressures in the compression cavities which are below pressures thatmight damage the vanes and other components of the compressor.

In order to maintain a minimum sealing load at the tangency seal line47, a helper spring 69 shown in FIGS. 3 and 7 is provided to rock thecylinder 44 about the pivot nose 48a so as to place a minimum load atthe tangency seal line 47. The spring 69 is in the form of a finger orleaf seated in a recess 70 in the outer face of the cylinder 44 andbottomed on a rib 71 of the housing 12. As shown in FIG. 7, the spring69 extends from the end plate 61 to the mouth 13 of the housing 12. Thespring is positioned in spaced relation downstream from the tangencyseal line 47 and since the pivot nose 49 is upstream from this tangencyseal line 47, the spring will rock the cylinder 44 into contact with therotor 36 at the tangency line 47.

As shown in FIG. 4, the refrigerant to be compressed enters the inletport 19 and in operation of the compressor a suction stop valve 72 inthe inlet port is unseated from its seat 73 to allow the refrigerant toflow through a screen 74 to an inlet port 75 on the inner face of theend head 11. This port 75 feeds the expanding cavities C and C betweenthe rotor 36 and cylinder 44 thereby drawing the refrigerant into thesuction side of the compressor. The valve 72 will not open unless thepressure in the cavities C and C is less than the pressure of therefrigerant being fed to the compressor. Thus, the valve is effective toclose for maintaining a negative pressure in the expanding cavities Cand C The refrigerant is then compressed in the contracting cavities Cand C to be discharged through the port holes 55 unseating the reedvalve 54 and enters the fibrous strip bounded chamber 56a. As explainedabove, the compressed refrigerant is then freed of its oil as it passesthrough the fibrous strips 57 and 60 into the main chamber 56 and isthen discharged through the port in the end head 11.

As illustrated in FIG. 8, the pressures designated by the arrows in thecontracting cavities C and C act on the cylinder 44 causing it to swingabout the pivot nose 48a in the direction shown by the arrow A. Thisswinging of the cylinder 44 will press it against the rotor 36 at thetangency seal line 47 thereby increasing the seal load as the pressuresin the contracting cavities C and C increase. Since the helper spring 69only maintains a very light sealing load at the tangency seal line 47and since the pressure developed by the operating compressor increasesthis load as needed to maintain a seal between the inlet and outletsides of the compressor, operating friction of the compressor isminimized without loss of sealing capacity.

From the above descriptions it should, therefore, be understood thatthis invention provides a tangency seal rotary fluid pressure apparatussuch as a pump, a motor or a compressor which develops its own tangencyseal pressure in operation, purges itself of liquid that might cause alock-up on rapid starting, separates liquid from compressed vapor or gasor lubricates the bearings and other components thereof with theseparated liquid. The preferred embodiment of the invention is a rotarysliding vane refrigerant compressor for automotive airconditioningsystems which has a free swinging eccentric cylinder guiding the vanesand loaded against the vane carrying rotor at a line of tangency bypressure of the refrigerant being compressed.

I claim as my invention:

1. In a tangency seal fluid pressure device of the type having a housingwith a fluid inlet and outlet, a rotor rotatably mounted in the housingand means projecting from the rotor acting on fluid between the inletand outlet, the improvement of a free swinging member in said housingeccentrically enveloping said rotor, guiding said means projecting fromthe rotor and pressed against the rotor along a line of tangency betweenthe member and rotor by pressures between the rotor and member, saidinlet and outlet communicating with the interior of the member onopposite sides of the tangency line.

2. A tangency seal fluid pressure apparatus which comprises a rotor,fixed bearings supporting the rotor, a member enveloping the rotor ineccentric relation therewith and defining expanding and contractingcavities around the rotor, fluid inlet and outlet means communicatingwith said cavities means carried by the rotor riding on said memberthrough said cavities, said member being sealed relative to the rotoralong a line of tangency between the minimum volume contracting andexpanding cavities, and a pivot support for said member accommodatingswinging of the member in response to pressures in the contractingcavities to increase the sealing pressure between the rotor andenveloping member at the line of tangency contact therebetween.

3. A tangency seal fluid pressure device comprising a housing, a rotorrotatably mounted in the housing, a cylinder swingable in the housingand surrounding the rotor in eccentric spaced relation therewith,members carried by the rotor riding on the inner wall of said cylinderdividing the space between the rotor and cylinder into expanding fluidreceiving cavities and contracting fluid expelling cavities, an inletport in the housing communicating with the expanding cavities, a pivotin the housingfor said cylinder, said pivot being positioned in thehousing relative to the contracting cavities so that pressure thereinwill swing the cylinder into sealing contact with the rotor along theline of tangency separating the expanding and contracting cavities, saidcylinder having a discharge opening therethrough immediately upstreamfrom the tangency line of contact with the rotor for discharging thefluid into the housing around the cylinder, and said housing having anoutlet port receiving said fluid.

4. A tangency seal rotary vane compressor comprising a housing having aninlet and an outlet, front and rear fixed bearing supports in saidhousing, bearing in said supports, a shaft rotatably carried by saidbearings, a rotor secured on said shaft for corrotation, said rotorhaving vane slots, vanes slidable in said slots, a cylinder swingable insaid housing surrounding said rotor and receiving the ends of the vanesin riding contact therewith, a pivot support for said cylinder in saidhousing accommodating swinging of the cylinder in response to fluidpressure between the rotor and cylinder for swinging the cylinder into atangency line contact with the rotor, said cylinder having outletopenings therethrough upstream from said tangency line contact with therotor, oil separating fibrous material between the housing and cylinderdefining with the housing and cylinder a first chamber receivingcompressed fluid from said outlet openings, said housing and cylinderdefining a second chamber receiving oil-freed fluid and separated oilpassed through the fibrous material from said first chamber, said outletdischarging the oil-freed compressed fluid from said second chamber, anoil collection sump between the housing and cylinder collecting oil inthe second chamber, means venting oil from said sump to the bearings,vanes and interior of the cylinder. a plate in the housingspring-pressed against an end of the cylinder and adapted to be unseatedfrom the cylinder by liquid compressed between the rotor and cylinderfor purging the liquid to the sump, and said inlet communicating withthe interior of the cylinder dow stream from the tangency line contactbetween the rotor and cylinder.

5. A self-oil purging rotary vane compressor adapted for compressingrefrigerant in automotive airconditioning systems which comprises an endhead having an inlet, an outlet, and a bearing supporting hub, acup-shaped housing piloted on said end head having a bearing supportinghub aligned with the hub of the end head, bearings in the hubs of theend head and housing, a shaft rotatably mounted in said bearings, a vanecarrying rotor mounted on said shaft between said bearings, a cylinderin said housing surrounding said rotor in eccentric relation and havingone end bottomed on said end head, a plate slidably piloted on the hubof said housing spring-pressed against the other end of said cylinder, apivot shoe carried by said housing cooperating with the outer peripheryof said cylin der accommodating swinging of the cylinder in the housingin response to pressures developed between the rotor and cylinder toload the cylinder against the rotor along a line of tangency, saidcylinder having openings therethrough joining the interior of thecylinder upstream from the tangency line of contact with the rotor todischarge fluid to the outlet, fibrous means in the path of the fluidbetween the openings in the cylinder and the outlet for separating oilfrom the fluid, said housing providing an oil collection sump in thebottom thereof receiving oil separated from the fluid, means in said endhead venting oil from the sump back to the bearings, vanes, and interiorof the cylinder, said plate adapted to be unseated from the cylinder tovent spaces between the rotor and cylinder to said sump to purge oilfrom the spaces, and said inlet communicating with the interior of thecylinder.

6. The apparatus of claim 2 wherein the pivot support for the member isa shoe cooperating with the outer periphery of the member.

7. The apparatus of claim 2 wherein a relief valve is provided to purgeliquid from the cavities between the rotor and member enveloping therotor upon development of excess pressures in the cavities.

8. The apparatus of claim 7 wherein the relief valve is a platespring-pressed against an end of the member enveloping the rotor.

9. The apparatus of claim 2 wherein the fixed bearings supporting therotor are carried by an end head and a cup-shaped housing piloted on theend head and cooperating with the end head to define an annular chambersurrounding the member receiving compressed fluid from the member.

10. The apparatus of claim 9 wherein fibrous strips are provided in theannular chamber between the member and housing to separate oil from thecompressed fluid received in the chamber.

11. The device of claim 3 including a shoe carried by the housingcooperating with the cylinder to form the pivot support therefor.

12. The device of claim 3 including a reed valve on the cylindercontrolling flow of fluid from the cxpelling cavities to the housing anda guard plate overlying the reed valve cooperating with a housingcarried shoe to form the pivot for the cylinder.

13. The device of claim 3 including a liquid purge valve cooperatingwith the cylinder to relieve liquid from the cavities to the housing.

14. The apparatus of claim 2 including a helper spring acting on themember enveloping the rotor to rock the member about the pivot supportfor maintaining a minimum pressure at the line of tangency between therotor and member.

15. The device of claim 3 wherein the pivot is positioned upstream fromthe line of tangency and a helper spring is positioned downstream fromsaid line of tangency for urging the cylinder to rock about its pivot tomaintain a minimum sealing load at the line of tangency between therotor and cylinder.

16. The device of claim 3 wherein the members carried by the rotorriding on the inner wall of the cylinder are sliding vanes.

17. The device of claim 3 having an annular chamber between the housingand the cylinder with fibrous strips isolating a sub-chamber receivingfluid from the discharge opening of the cylinder effective to separateliquid entrained with the compressed fluid.

18. The device of claim 17 wherein the annular chamber has a collectionsump for the separated liquid.

19. The device of claim 3 including a spring loaded plate engaging oneend of the cylinder and adapted to be deflected from said one end toprovide a relief pas sage connecting the cavities between the rotor andcylinder with the interior of the housing.

20. The compressor of claim 4 wherein the rotor has four radial vanesand springs urging said vanes outwardly from said slots to engage thecylinder.

21. The compressor of claim 4 wherein the housing includes an endbearing plate with the inlet and outlet and a cup-shaped housing memberpiloted on the bearing plate providing the rear bearing support.

22. The compressor of claim 4 wherein the fibrous material separatingthe first and second chambers are strips on nonmetallic high-temperatureresisting fibers.

23. The compressor of claim 4 wherein the cylinder has one end bottomedagainst an end of the housing and a spring loaded relief plate ispressed against the other end of the cylinder and wherein the first andsecond chambers are separated by two radial strips of fibrous materialbetween the cylinder and periphery of the housing and a third strip offibrous material between the plate and back wall of the housing.

24. The compressor of claim 4 wherein the pivot support for the cylinderincludes a rigid plate bolted to the periphery of the cylinder andhaving a recess midway between the ends of the cylinder and a shoecarried by the housing seats in said recess.

25. The compressor of claim 4 including bleeder holes through thecylinder immediately adjacent the upstream side of the tangency linecontact with the rotor to vent liquid to the first chamber.

26. The method of sealing a rotor and an eccentric cylinder envelopingthe rotor along a tangency line therebetween in a tangency seal fluidpressure device which comprises rocking the cylinder about a pivotupstream from the tangency line against the rotor with pressuredeveloped by the device between the rotor and cylinder.

1. In a tangency seal fluid pressure device of the type having a housingwith a fluid inlet and outlet, a rotor rotatably mounted in the housingand means projecting from the rotor acting on fluid between the inletand outlet, the improvement of a free swinging member in said housingeccentrically enveloping said rotor, guiding said means projecting fromthe rotor and pressed against the rotor along a line of tangency betweenthe member and rotor by pressures between the rotor and member, saidinlet and outlet communicating with the interior of the member onopposite sides of the tangency line.
 2. A tangency seal fluid pressureapparatus which comprises a rotor, fixed bearings supporting the rotor,a member enveloping the rotor in eccentric relation therewith anddefining expanding and contracting cavities around the rotor, fluidinlet and outlet means communicating with said cavities means carried bythe rotor riding on said member through said cavities, said member beingsealed relative to the rotor along a line of tangency between theminimum volume contracting and expanding cavities, and a pivot supportfor said member accommodating swinging of the member in response topressures in the contracting cavities to increase the sealing pressurebetween the rotor and enveloping member at the line of tangency contacttherebetween.
 3. A tangency seal fluid pressure device comprising ahousing, a rotor rotatably mounted in the housing, a cylinder swingablein the housing and surrounding the rotor in eccentric spaced relationtherewith, members carried by the rotor riding on the inner wall of saidcylinder dividing the space between the rotor and cylinder intoexpandinG fluid receiving cavities and contracting fluid expellingcavities, an inlet port in the housing communicating with the expandingcavities, a pivot in the housing for said cylinder, said pivot beingpositioned in the housing relative to the contracting cavities so thatpressure therein will swing the cylinder into sealing contact with therotor along the line of tangency separating the expanding andcontracting cavities, said cylinder having a discharge openingtherethrough immediately upstream from the tangency line of contact withthe rotor for discharging the fluid into the housing around thecylinder, and said housing having an outlet port receiving said fluid.4. A tangency seal rotary vane compressor comprising a housing having aninlet and an outlet, front and rear fixed bearing supports in saidhousing, bearing in said supports, a shaft rotatably carried by saidbearings, a rotor secured on said shaft for corrotation, said rotorhaving vane slots, vanes slidable in said slots, a cylinder swingable insaid housing surrounding said rotor and receiving the ends of the vanesin riding contact therewith, a pivot support for said cylinder in saidhousing accommodating swinging of the cylinder in response to fluidpressure between the rotor and cylinder for swinging the cylinder into atangency line contact with the rotor, said cylinder having outletopenings therethrough upstream from said tangency line contact with therotor, oil separating fibrous material between the housing and cylinderdefining with the housing and cylinder a first chamber receivingcompressed fluid from said outlet openings, said housing and cylinderdefining a second chamber receiving oil-freed fluid and separated oilpassed through the fibrous material from said first chamber, said outletdischarging the oil-freed compressed fluid from said second chamber, anoil collection sump between the housing and cylinder collecting oil inthe second chamber, means venting oil from said sump to the bearings,vanes and interior of the cylinder, a plate in the housingspring-pressed against an end of the cylinder and adapted to be unseatedfrom the cylinder by liquid compressed between the rotor and cylinderfor purging the liquid to the sump, and said inlet communicating withthe interior of the cylinder dowstream from the tangency line contactbetween the rotor and cylinder.
 5. A self-oil purging rotary vanecompressor adapted for compressing refrigerant in automotiveair-conditioning systems which comprises an end head having an inlet, anoutlet, and a bearing supporting hub, a cup-shaped housing piloted onsaid end head having a bearing supporting hub aligned with the hub ofthe end head, bearings in the hubs of the end head and housing, a shaftrotatably mounted in said bearings, a vane carrying rotor mounted onsaid shaft between said bearings, a cylinder in said housing surroundingsaid rotor in eccentric relation and having one end bottomed on said endhead, a plate slidably piloted on the hub of said housing spring-pressedagainst the other end of said cylinder, a pivot shoe carried by saidhousing cooperating with the outer periphery of said cylinderaccommodating swinging of the cylinder in the housing in response topressures developed between the rotor and cylinder to load the cylinderagainst the rotor along a line of tangency, said cylinder havingopenings therethrough joining the interior of the cylinder upstream fromthe tangency line of contact with the rotor to discharge fluid to theoutlet, fibrous means in the path of the fluid between the openings inthe cylinder and the outlet for separating oil from the fluid, saidhousing providing an oil collection sump in the bottom thereof receivingoil separated from the fluid, means in said end head venting oil fromthe sump back to the bearings, vanes, and interior of the cylinder, saidplate adapted to be unseated from the cylinder to vent spaces betweenthe rotor and cylinder to said sump to purge oil from the spaces, andsaid inlet communicatinG with the interior of the cylinder.
 6. Theapparatus of claim 2 wherein the pivot support for the member is a shoecooperating with the outer periphery of the member.
 7. The apparatus ofclaim 2 wherein a relief valve is provided to purge liquid from thecavities between the rotor and member enveloping the rotor upondevelopment of excess pressures in the cavities.
 8. The apparatus ofclaim 7 wherein the relief valve is a plate spring-pressed against anend of the member enveloping the rotor.
 9. The apparatus of claim 2wherein the fixed bearings supporting the rotor are carried by an endhead and a cup-shaped housing piloted on the end head and cooperatingwith the end head to define an annular chamber surrounding the memberreceiving compressed fluid from the member.
 10. The apparatus of claim 9wherein fibrous strips are provided in the annular chamber between themember and housing to separate oil from the compressed fluid received inthe chamber.
 11. The device of claim 3 including a shoe carried by thehousing cooperating with the cylinder to form the pivot supporttherefor.
 12. The device of claim 3 including a reed valve on thecylinder controlling flow of fluid from the expelling cavities to thehousing and a guard plate overlying the reed valve cooperating with ahousing carried shoe to form the pivot for the cylinder.
 13. The deviceof claim 3 including a liquid purge valve cooperating with the cylinderto relieve liquid from the cavities to the housing.
 14. The apparatus ofclaim 2 including a helper spring acting on the member enveloping therotor to rock the member about the pivot support for maintaining aminimum pressure at the line of tangency between the rotor and member.15. The device of claim 3 wherein the pivot is positioned upstream fromthe line of tangency and a helper spring is positioned downstream fromsaid line of tangency for urging the cylinder to rock about its pivot tomaintain a minimum sealing load at the line of tangency between therotor and cylinder.
 16. The device of claim 3 wherein the memberscarried by the rotor riding on the inner wall of the cylinder aresliding vanes.
 17. The device of claim 3 having an annular chamberbetween the housing and the cylinder with fibrous strips isolating asub-chamber receiving fluid from the discharge opening of the cylindereffective to separate liquid entrained with the compressed fluid. 18.The device of claim 17 wherein the annular chamber has a collection sumpfor the separated liquid.
 19. The device of claim 3 including a springloaded plate engaging one end of the cylinder and adapted to bedeflected from said one end to provide a relief passage connecting thecavities between the rotor and cylinder with the interior of thehousing.
 20. The compressor of claim 4 wherein the rotor has four radialvanes and springs urging said vanes outwardly from said slots to engagethe cylinder.
 21. The compressor of claim 4 wherein the housing includesan end bearing plate with the inlet and outlet and a cup-shaped housingmember piloted on the bearing plate providing the rear bearing support.22. The compressor of claim 4 wherein the fibrous material separatingthe first and second chambers are strips on nonmetallic high-temperatureresisting fibers.
 23. The compressor of claim 4 wherein the cylinder hasone end bottomed against an end of the housing and a spring loadedrelief plate is pressed against the other end of the cylinder andwherein the first and second chambers are separated by two radial stripsof fibrous material between the cylinder and periphery of the housingand a third strip of fibrous material between the plate and back wall ofthe housing.
 24. The compressor of claim 4 wherein the pivot support forthe cylinder includes a rigid plate bolted to the periphery of thecylinder and having a recess midway between the ends of the cylinder anda shoe carried by the housing seats in said recess.
 25. The compressorof claim 4 including Bleeder holes through the cylinder immediatelyadjacent the upstream side of the tangency line contact with the rotorto vent liquid to the first chamber.
 26. The method of sealing a rotorand an eccentric cylinder enveloping the rotor along a tangency linetherebetween in a tangency seal fluid pressure device which comprisesrocking the cylinder about a pivot upstream from the tangency lineagainst the rotor with pressure developed by the device between therotor and cylinder.